J.J. Spaun sat quietly Tuesday morning at Shinnecock Hills while USGA officials conducted a media day presentation for next month’s U.S. Open at the venerable Long Island 18-hole icon.

“I still can’t believe I won this tournament, honestly,’’ Spaun said, sounding like the most humble major champion ever.

The 35-year-old Spaun, a late bloomer, will defend his title when the first round begins at Shinnecock on June 18.

He called his existence the past 11 months as the reigning U.S. Open champion, in only his second start in the major, “very strange.’’

“I remember getting to the Travelers Championship [the week after the U.S. Open] and I was paired with Scottie [Scheffler, the world No. 1] and all of a sudden there were like 10,000 people around the first tee,’’ Spaun said. “I got to go first, which was nice. They announced me as the U.S. Open champion and it was almost like I had to step off and really let that sink in … just to hear the crowd go crazy.

“It was almost like a louder roar for me than when they introduced Scottie. So that felt good for once. But it was so surreal. Whether I’m not feeling great confidence-wise or whatever, just to hear that every time I tee off is just a really good feeling to inspire myself again, whatever may be going on, just to reflect on what I accomplished. I’m just so honored to be the U.S. Open champion.”

Spaun struggled early in the season with four missed cuts in his first seven events with a top finish tying for 24th.

Then he won the Valero Texas Open in April, feeling like he “validated’’ his U.S. Open win. But then he missed the cut at the Masters. Last week in the Cadillac Championship at Doral he finished in a tie for 14th.

Tuesday was Spaun’s first time at Shinnecock.

“It’s nice stepping onto the property just to get familiarized with what to expect visually and get logistically comfortable with what’s going on,’’ he said. “But with majors, I try not to dwell too much. I’ve learned my lesson. My first time playing the Masters, I won the week before so I kind of rushed there, and I played fine.

“Then the second time I wanted to really take my time, so I got there Saturday and I didn’t play great. I felt like I was there waiting for Thursday [the opening round] way too long.’’

He said he changed his schedule for last year’s U.S. Open at Oakmont to arrive Sunday.

“Even though I’d never been there, I felt like that was plenty of time to prepare,’’ he said. “I’ll probably do the same thing here … get here Sunday, be on the course Monday, Tuesday, Wednesday. I’ll just try to kind of do what I did last year. It seemed to have worked.”